For example, a vehicle such as an automobile is provided with an air conditioner to perform temperature adjustment in a vehicle interior. Such an air conditioner includes a loop-like refrigerant cycle to circulate a refrigerant (cooling medium). The refrigerant cycle is provided with an evaporator, a compressor, a condenser and an expansion valve which are arranged in order.
The compressor of the air conditioner compresses a gas-like refrigerant (refrigerant gas) evaporated by the evaporator to form a high-pressure refrigerant gas and sends it to the condenser.
A vane rotary type compressor is conventionally known as an example of the gas compressor (for reference, see Patent Literature 1). In the vane rotary type compressor, a rotor having a plurality of vanes is rotatably disposed in a cylinder having a generally elliptic inner peripheral surface. The vanes are provided in the rotor to be movable in a radial direction of the rotor, and are configured such that a leading end portion of each vane is in slide-contact with the inner peripheral surface of the cylinder.
The vane rotary type compressor includes compression chambers each having a capacity changed by the slide-contact of the vanes with the inner peripheral surface of the cylinder as the vanes rotate in accordance with the rotation of the rotor. The compressor is configured to suck a refrigerant gas through a suction port as the capacity of each of the compression chambers increases, compress the sucked refrigerant gas as the capacity of each of the compression chambers decreases, and discharge the high-pressure refrigerant gas to a discharge chamber through a discharge port. Next, the compressor supplies the high-pressure refrigerant gas from the discharge chamber to a condenser side.
In addition, the vanes are slidably disposed in slit-shaped vane grooves extending from an inner side to an outer side of the rotor. Each of the vanes is moved by a back pressure (vane back pressure) of oil supplied to a bottom portion in the vane groove through a vane back pressure space and so on and by a centrifugal force of the rotating rotor such that a leading end portion of the vane projects from a surface of the rotor to maintain a state which is in contact with the inner peripheral surface of the cylinder.